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Tidal Volume related to AHIs?
#11
(03-12-2017, 01:41 PM)chill Wrote:
(03-12-2017, 04:11 AM)Hydrangea Wrote: What do you mean by "to see if it improves your breathing"?  What would improvement look like?  More consistent rhythm?  Not shallow breathing?  Or just decreasing the precursors of apneas?

Decreasing the precursors.  The pressure of anything other than ASV is not enough to meaningfully affect the inflation of your lungs.

Ah ok. 

I feel so bad for following up with more questions... but I really want to understand what is going on when I sleep with something every night. <snicker>

So what is the purpose of the pressure from a CPAP?  Does it just remind the throat to let air pass?  And some people need higher pressures because their throats are weaker/stronger?  

Sleeprider - So a CPAP/APAP does not offer "pressure support", rather it offers "pressure"?  I really have not comprehended what pressure support is, and how it varies from the Flex setting on my machine.
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#12
(03-12-2017, 03:02 PM)Hydrangea Wrote: I feel so bad for following up with more questions... but I really want to understand what is going on when I sleep with something every night. <snicker>

So what is the purpose of the pressure from a CPAP?  Does it just remind the throat to let air pass?  And some people need higher pressures because their throats are weaker/stronger?

More questions are good.

Put on your mask and turn on the machine.  Close your lips.  Relax your tongue and push it to the bottom of your mouth.  What happens to your cheeks? That is what the CPAP is doing to your throat.  Granted, your throat probably less inflatable than your cheeks.
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#13
(03-12-2017, 03:02 PM)Hydrange Wrote: Sleeprider - So a CPAP/APAP does not offer "pressure support", rather it offers "pressure"?  I really have not comprehended what pressure support is, and how it varies from the Flex setting on my machine.

I added a definition to the Wiki, and have started an article on Pressure Support.  That one is going to be a little more involved, but I appreciate the question since that is clearly a missing link in our information here.

'''Definition:'''

Pressure support (PS) in positive air pressure therapy, is the difference between inspiratory positive air pressure (IPAP) and expiratory positive pressure (EPAP). For example if IPAP is set at 12 and EPAP is set at 8 the PS is 12 - 8 = 4.0.
Flex and EPR are not nearly the same.

EPR lowers the pressure during the entire exhale cycle by 1 to 3 cm of pressure. EPR ends upon spontaneous inhale. If you have an apnea, the pressure stays low.

Flex provides pressure relief up to 2 cm at the beginning of exhale, an it returns to CPAP pressure before exhalation ends.

This figure shows the mask pressure (blue) compared to the respiratory flow rate (black) with EPR at 3 cm. An apnea in this image shows the pressure does not rise until the apnea is over. Resmed EPR can result in pressures lower than the titrated pressure that prevents OA.

[Image: wxNRuZuh.png]


Flex relief is at the beginning of exhale, but returns to CPAP pressure before exhale ends. Flex has the advantage that the prescribed pressure is not affected, but it does not have the same comfort effect.

[Image: c-flex-technology.jpg]
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#14
Disclaimer: I am not trying to start an argument with you, just noting a difference in terminology that may cause confusion.

https://en.wikipedia.org/wiki/Pressure_s...entilation has a different definition of the term: "Pressure support ventilation (PSV), also known as pressure support, is a spontaneous mode of ventilation. The patient initiates every breath and the ventilator delivers support with the preset pressure value. With support from the ventilator, the patient also regulates his own respiratory rate and tidal volume.".

This may be a useful reference for your article.
http://www.lakesidepress.com/CPAP/CPAP.htm
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#15
(03-12-2017, 07:05 PM)chill Wrote: Disclaimer: I am not trying to start an argument with you, just noting a difference in terminology that may cause confusion.

https://en.wikipedia.org/wiki/Pressure_s...entilation has a different definition of the term: "Pressure support ventilation (PSV), also known as pressure support, is a spontaneous mode of ventilation. The patient initiates every breath and the ventilator delivers support with the preset pressure value. With support from the ventilator, the patient also regulates his own respiratory rate and tidal volume.".

This may be a useful reference for your article.
http://www.lakesidepress.com/CPAP/CPAP.htm

That is partially correct, but pressure support is also used in both invasive and noninvasive ventilation support.  In the context of bilvell therapy, pressure support is the force that maske AVAPS, ASV, ST, and all other forms of bilvel/BiPAP work.  That's the reason this is not going to be published tonight. Smile
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#16
I am looking forward to it.  I've learned a lot from you in the past few weeks on related topics.
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